I have a new house being built, and of course am running into brick
walls with the HVAC contractor. He is more accustomed to commercial
and industrial buildings where all the thinking and engineering has
been done for him, so all he has to do is install.
What I want is hydronic heat, under the floor, stapled up between floor
joists (over an unfinished basement that also has foam insulation on
the outside of the exterior walls). I plan on using foam board with
foil on one side, cut to fit loosely enough to be easily installed
and/or removed from the engineered joists.
That will be the base load, but as we all know, changing the
temperature of a hydronic system takes hours. So, since we have to
pre-wire, pre-plumb, etc. for a forced air system anyway for air
conditioning (not my idea, but making sure that the house can be sold
someday without major mods), I want a hot water coil in the air handler
to boost the air temperature in those occasional events when the
domestic supervisor is cold and wants heat right NOW. She tends to run
thermostats either all the way up or down, thinking she will reach her
comfort zone faster that way. Really irritating in the car, I can tell
That is the heating side of it, from my viewpoint. He says a simple
gas furnace is the way to go, because that is pretty much what he does
in houses. A compromise would be a modern gas furnace with 2 levels
of heating, and 2 fan speeds that won't have to run very often based on
the hydronic doing most of the work.
HVAC guy also wants me to put in 4 to 5 tons of AC for a house in
Logan, Utah. I only have 4 tons for our house in Phoenix, Arizona, and
it gets a bit hot there. The Utah house is smaller by 150 sq. ft. but
also has a 900 sq. ft. loft and bonus room area upstairs that is pretty
much open to the main floor. We won't be going up there much, though.
I warned him about oversizing, letting him know that I could live with
a system that runs too often or too long than one that short cycles. I
can always add to the hydronic if I have to.
I won't put in the outside portion of the AC for at least the first
year, thinking that I have designed the house well enough to need very
little cooling assistance, and if it does, I prefer either a whole
house fan, or evaporative cooling.
Does this sound like sound, and sane, thinking on my part?